Interrupting structures for compressedgas circuit interrupters having double-break hollow rotative moving contact-arm assembly



Dec. 13, 1966 7 4 9 .l 11 9 ZTE 3 M V on R T A C T O S R mwv wvl E L .M SOM EMHE LR K KWMA CO R M 'ICB S R R R. C. VAN INTERRUPTING STRUCTURES FO INTERRUPTERS HAVING DOUBLE MOVING CONTACT-A Filed June 12, 1964 17 Sheets-Sheet l Dec. 13,. 1966 R. c. VAN slcKLE 3,291,947

-GAS CIRCU INTERRUPTING STRUCTURES FOR COMPRESSED IT INTERRUPTERS HAVING DOUBLE-BREAK HOLLOW ROTATIVE MOVING CONTACT-ARM ASSEMBLY 17 Sheets-Shea?l 2 Filed June l2, 1964 Dec. 13,` 1966 R. c. VAN slcKLE 3,291,947

ES FOR COMPRESSED-GAS CIRCUIT INTERRUPTING STRUCTUR INTERRUPTERS HAVING DOUBLE-BREAK HOLLOW ROTATIVE MOVING CONTACT-ARM ASSEMBLY Filed June 12, 1964 f' 17 Sheets-Sheet I5 wmv l l Il. I Il In n INVENTOR Roswell C. VonSickle ff M ATTORNEY Dec. 13, 1966 R c. VAN sxcKLE 3,291,947

INTERRUPTING STRUCTURES FOR COMPRESSED-GAS CIRCUIT INTERRUPTERS HAVING DOUBLE-BREAK HOLLOW ROTATIVE MOVING CONTACT-#IRM ASSEMBLY Filed June l2, 1964 17 Sheets-Sheet 4 Fig.4.

R. c. VAN slcKLE: 3,291,947

MOVING CONTACT-ARM ASSEMBLY 17 Sheets-Sheet 5 vom A iv u wow Dec. 13, 1966 INTERRUPTING STRUCTURES FOR COMPRESSED-GAS CIRCUIT INTERRUPTERS HAVING DOUBLE-BREAK HOLLOW ROTA`TIVE Filed June 12, 1964 Dec. 13, 1966 R. c. VAN slcKLE 3,291,947

INTERRUPTING STRUCTUR FOR PRESSED-GAS CIRCUIT INTERRUPT HAVING BLE- AK H OW ROTATIVE VING CONTACT-ARM ASSEM Y Filed June 12, 1964 17 Sheets-Sheet 6 Dec. 13, 1966 .c. VAN SICKLE 3,291,947

INTERRUPTING STRUCTURES FOR COMPRES5ED-GAS CIRCUIT INTERRUPTERS HAVING DOUBLE-BREAK HOLLOW ROTATIVE MOVING CONTACT-ARM ASSEMBLY Filed June l2, 1964 n y 17 Sheets-Sheet 7 |72 Fig.7A.

|64 aloJ 314 /f Dec. 13, 1966 R. c. VAN slcKLE 3,291,947

INTERRUPTING STRUCTURES FOR COMPRESSED-GAS CIRCUIT` INTERRUPTERS HAVING DOUBLE-BREAK HOLLOW ROTATIVE MOVING CONTACT-ARM ASSEMBLY 2 Filed June l2, 1964 17 Sheets-Sheet 8 BOO 298 302 27e l I 27a I Fig. 8.

De@ 13, 1965 c. VAN slcKLE 3,291,947

INTERRUPTING STRUOTURES FOR COMPRESSED-GAS CIRCUIT INTERRUPTERS HAVING DOUBLE-BREAK HOLLOW ROTATIVE MOVING CONTACT-ARM ASSEMBLY Filed June 12, 1964 17 Sheets-Sheet 9 Dec. 13, 1966 A .c. VAN sl L E 3,291,947

INTERRUPTING S CTURES C RES -GAS CIRCUIT INTERRUPTERS HAVING DOUB -BR H OW ROTATIVE VING CONTACT-ARM EMBLY Filed June l2, 1964 17 Sheets-Sheet l0 l l a l Dec. 13, 1966 R. c. VAN SICKLE INTERRUPTING STRUCTURES FOR COMPRESSED-GAS CIRCUIT INTERRUPTERS HAVING DOUBLE-BREAK HOLLOW ROTATIVE MOVINGKCONTACT-ARM ASSEMBLY i 17 Sheets-Sheet l1 Filed June 12,. 1964 Dec. 13, 1966 R. c. VAN slcKL 3,291,947

INTERRUPTING STRUCTURES FOR COMPRESSED-GAS CIRCUIT INTERRUPTERS HAVING DOUBLE-BREAK HOLLOW ROTATIVE MOVING CONTACT-ARM ASSEMBLY Filed June l2, 1964 17 Sheets-Sheet 12 f l 1 i 254 g i I l i l .I

F ig.l7.

3,291,947 UIT Dec. 13, 1966 R. c. VAN slcKLE INTERRUPTING STRUCTURES FOR COMPRESSED-GAS CIRC INTERRUPTERS HAVING DOUBLE-BREAK HOLLOW ROTATIVE MOVING CONTACT-ARM ASSEMBLY 17 Sheets-Sheet 15 Filed June l2, 1964 2 Kill Fig.l8.

226 Fig. 22.

3. 2 .nlw F Dec. 13, 1966 R. c. VAN slcKLE 3,291,947

INTERRUPTING STRUCTURES FOR COMPRESSED-GAS C UIT INTERRUPT AVING DOU HOLL H BLE-BR OW ROT VE VING CONTACT-ARM EMBLY Filed June l2, 1964 17 Sheets-Sheet 14 Dec. 13, 1966 Filed June l2,

R. C. VAN SICKLE INTERRUPTING STRUCT URES FOR COMPRESSED-GAS CIRCUIT INTERRUPTERS HAVING DOUBLE-BREAK HOLLOW ROTATIVE MOVING CONTACT-ARM ASSEMBLY 17 Sheets-Sheet l5 Dec. 13, 1966 l R, VAN S,CK. E 3,291,947

INTERRUPTING STRUCTURES FOR COMPRESSED-GAS CIRCUIT INTERRUPTERS HAVING DOUBLE-BREAK HOLLOW ROTATIVE MQVING CONTACT-ARM ASSEMBLY Filed June 12, 1964 17 Sheets-Sheet 16 Dec. 13, 1966 R. c. VAN slcKLE 3,291,947

INTERRUPTING STRUCTURES FOR COMPRESSED-GAS CIRCUIT INTERRUPTERS HAVING DOUBLE-BREAK HOLLOW ROTATIVE MOVING CONTACT-ARM ASSEMBLY Filed June 12, 1964 17 Sheets-Sheet 17 PER UNIT OF NORMAL CREST VOLTAGE 6 2 3 SURGE IMPEDANCE United States Patent O "a INTERRUPTING STRUCTURES FOR COMPRESSED- GAS CIRCUIT INTERRUPTERS HAVING DOU- BLE-BREAK HOLLGW ROTATIVE MOVING CON- TACT-ARM ASSEMBLY Roswell C. Van Sickle, Wilkinsburg, Pa., assignor to Westinghouse Electric Corporation, Pittsburgh, Pa., a corporation of Pennsylvania Filed June 12, 1964, Ser. No. 374,708 16 Claims. (Cl. 200-148) This invention relates generally to interrupting structures and operating mechanisms for compressed-gas circuit interrupters and, more particularly, to improved and highly-efcient compressed-gas circuit interrupters suitable for use over a wide voltage and current range.

A general object of the present invention is the provision of an improved compressed-gas circuit interrupter adaptable for high-speed operation, and suitable for multiple-series use in the higher-voltage ranges.

Another object of the present invention is the provision of an improved interrupting head for a high-voltage line of compressed-gas circuit interrupters.

Still a further object of the present invention is the provision of a high-speed compressed-gas circuit interrupter of the type utilizing two breaks in series, in which the inertia of the rotating, or moving parts is maintained at a minimum.

Another object of the present invention lis the provision of an improved compressed-gas circuit interrupter utilizing a highly-eicient blast-valve mechanism, the latter being disposed at a highly strategic location relative to the two interrupting 4units to result in a minimum of elapsed time p'rior to the ejection of a blast of arc-extinguishing gas into the region between the separated contact structure during the opening operation.

Still a further object of thel present invention is the provision of an improved compressed-gas circuit interrupter of the rotating cross-arm type in which the rotating hub :assembly has associated therewith a novel blastvalve mechanism.

Another object of the present invention is the provision of an improved modular compressed-gas interrupting head, which is suitable, in multiple series arrangements, for the higher-voltage ranges.

Still a further object of the present invention is the provision of an improved circuit interrupter in -which an impedance means, such as a resistor, is inserted into series circuit only `during the closing operation of the circuit interrupter to damp the accompanying voltage surges on the line. This has the important advantage that voltage surges on the line are damped on closing, but yet a fast interrupting time, such as two-cycle operation for complete clearing of the circuit, is achieved by the elimination of a two-step opening operation with a resistor.

Still a further object of the present invention is the provision of an improved voltage-dividing means associated with a multiple series-break type of circuit `interrupter.

Another object of the present invention is the provision of an improved resistor assemblage conveniently and compactly located relative to -interiorly-extending terminal bushings protruding into a substantially enclosed interrupting head.

Another object of the present invention is the provision of an improved simplified-type of compressed-gas interrupting head in which maintenance operations are easily and readily achieved, and in which the inertia of the movingI parts -is maintained at a minimum.

Another object of the present invention is the provision of an improved compressed-gas interrupting assemblage involving a pair of serially-related breaks, in which each 3,291,947 Patented Dec. 13, 1966 ICC break has associated therewith a novel orifice construction, and in which double-venting action is achieved during circuit interruption.

In U.S. patent application tiled June 8, 1964, Serial No. 373,150 by Robert G. Colclaser, Ir., and Frank L. Reese, and assigned to the `assignee of the instant application, there is disclosed and described a high-voltage compressed-gas circuit interrupter in which a rotating operating-rod construction is utilized in connection with a pair of lserially-related interrupting units disposed within a surrounding tank structure. In the aforesaid patent application, rotation of the operating rod not only achieves, through rotating action, separation at the contact structures of the pair ;of serially-related interrupting units, but, in addition, compressed gas is caused to flow through the rotating operating rod and radially outwardly through the pair of tubular movable contacts. It is a further object of the present invention to improve upon the interrupting construction set forth in the aforesaid patent application, rendering it more suitable for multiple modular use and, in addition, rendering more compact the parts associated therewith. c

Further objects `and advantages will readily become apparent upon reading the following specification, taken in conjunction with the drawings, in which:

FIGURE 1 is a side elevational view of a three-phase high-voltage compressed-gas circuit interrupter embodying the principles of the present invention;

FIG. 2 is an end elevational view of the three-phase circuit interrupter illustrated 4in FIG. 1;

FIG. 3 is a vertical sectional view taken through one of the modular interrupting heads of one of the pole-units of the circuit interrupter of FIGS. l and 2, taken substantially along the line III III of FIG. 2, with the separable contact structure being illustrated in the closed-circuit position;

FIG. 4 is a vertical sectional view taken substantially along the line IV-IV of FIG. 3 with the resistor and Voltage-dividing assembly omitted for clarity;

FIG. 5 is a horizontal sectional view taken substantially along the line V-V of FIGS. 3 and 4;

FIG. 6 is an enlarged fragmentary vertical sectional view, somewhat similar to that of FIG. 3, but showing the disposition of several detailed contact parts in the partially-open position;

FIG. 7 is an enlarged fragmentary view of the blastvalve showing the open position thereof, taken substantially along the line VII-VII of FIG. 4;

FIG. 7A is a view similar to that of FIG. 7, but showing the blast-valve in the closed position thereof;

FIG. 8 is an enlarged side elevational view of a portion of the operating linkage and the blast-valve mechanism taken substantially along the line VIII-VIII of FIG. 5;

FIG. 9 is a fragmentary enlarged vertical sectional view taken through a portion of the blast-valve linkage, the view being taken substantially along the line IX-IX of FIG. 8;

FIG. 10 is an enlarged detailed sectional view of the operating linkage, the view being taken substantially along the line X-X of FIG. 8;

FIG. 11 is a longitudinal sectional view taken through the torsion-bar spring assembly;

FIG. l2 is a side elevational view of the closing resistor assemblage and the stationary resistor contact taken substantially along the line XII-XII of FIG. 5;

FIG. 12A is an enlarged fragmentary view of a portion of the spring plate of FIG. 12, taken substantially along the line A-A thereof;

FIG. 13 is a vertical sectional view taken substantially along the line XIII-XIII of FIG. 12;

FIG. 14 is a detail front elevational view of the blastvalve operating lever;

FIG. 15 is a vertical sectional view taken substantially along the line XV-XV ofthe blast-valve operating lever of FIG. 14;

FIG. 16 is an enlarged side elevational View of the blastvalve operating cam;

FIG. 17 is a top plan view of the blast-valve operating cam illustrated in FIG. 16;

FIG. 18 is a side elevational view of a blast-valve camoperating lever;

FIG. 19 is a side elevational view of the blast-valve camoperating lever of FIG. 18;

FIG. 20 is a side elevational view of a blast-valve releasing bracket;

FIG. 21 is an end elevational view of the blast-valve releasing bracket of FIG. 20;

FIG. 22 is a side elevational view of one of the releasable blast-valve dogs;

FIG. 23 is an end elevational view of the releasable blast-valve dog of FIG. 22;

FIG. 24 is a side elevational view of the main operating lever for the modular interrupting head of FIG. 3;

FIG. 25 is a sectional view taken substantially along the line XXV-XXV of FIG. 24;

FIG. 26 is an end elevational view of the main operating lever of FIGS. 24 and 25;

FIG. 27 is a top plan view of the main operating lever of FIGS. 24-26;

FIG. 28 is a top plan view of the main stationary support frame for the modular interrupting head of FIG. 3;

FIG. 29 is a side elevational view of the main stationary frame support of FIG. 28;

FIG. 30 is an end elevational View of the main stationary support frame of FIGS. 28 and 29;

FIG. 31 is a diagrammatic view illustrating an improved voltage-dividing impedance arrangement for a multiple-break type of circuit interrupter, embodying principles of the present invention;

FIG. 32 is a somewhat simplified diagrammatic view of the operating linkage at the base of one of the poleunits of the present invention;

FIG. 33 is a diagrammatic view of the closing resistor and contact arrangement with the contacts shown in the open position; and

` FIG. 34 illustrates curves of surge voltage a function of closing resistance values.

With reference to FIGS. 1 and 2 of the drawings, it Will be noted that there is shown a high-voltage three-phase compressed-gas circuit interrupter including pole-units A, B and C. The pole units are alike except for the interpole electrical control wiring, gas lines and air lines and for the house lon the middle pole which contains the common parts of the air and gas systems. Each pole-unit A, B or C is mounted upon a heavy grounded supporting frame 12 comprising heavy longitudinally-extending beam members 14 and angularly braced supports 16. In addition, each supporting frame 12 preferably has a longitudinally-extending high-pressure main reservoir tank 18 associated therewith, extending in generally parallel relationship, having individual supply pipes 20 extending upwardly therefrom into three insulating upstanding column structures 22 to supply high-pressure gas to auxiliary highpressure reservoir chambers 24 at high potential, as more particularly described hereinafter.

Associated with each pole-unit A, B lor C is an upstanding current-transformer assembly or structure 26, which is utilized to measure the current iiow through the pole-unit. Since the current-transformer structure 26 constitutes no part of the present invention, and the internal structure thereof is well understood by those skilled in the art, it will not be described. Reference may, however, be made to U.S. Patent 2,504,647 for a description of a typical gaslled type of current transformer, which could be used,

magnitude as As shown in FIGS. 1 and 2, surmounted upon the insulating column structures 22 are live metallic exhaust housings, or interrupting head-units 28 at high potential, interiorly of each of which is a pair of serially-related arc-extinguishing units 30, m-ore particularly illustrated in FIGS. 3 and 6 of the drawings.

g An-inspection door 32 (FIG. 5), pivotally supported upon hinge pins 34, may be secured by bolts 36, as shown in FIG. 5, to form a gas-tight closure for the head-unit 28.

With respect to FIG. 3 of the drawings, it will be noted that each interrupting head-unit 28 comprises a rotating bridging contact cross-arm assembly, generally designated by the reference numeral 38, and including a pair of radially outwardly-extending gas-conducting arms 40 carrying movable contacts 42. Each movable contact 42 separates fromv a relatively stationary contact structure 44 to establish an arc 46 (FIG. 6), which is extinguished by an intensive gas flow, as more fully described hereinafter. The stationary contacts 44 are supported and clamped to terminal studs 48 extending through terminal bushings 50, the latter protruding through the ends of the interrupting head-units 28. Generally, the circuitinterrupting structure 10 operates, during the opening and closing operations, so as to effect rotation of the several cross-arm assemblies 38 to consequently bring about a closing, or alternatively, an interruption of the electrical circuit L1L2, through the circuit interrupter 10.

With reference to FIG. 32 of the drawings, it will be noted that there is provided a mechanism compartment 52 containing asuitable operating mechanism 54. The operating mechanism 54 constitutes no part of the present invention, and may be a hydraulic type, pneumatic type or a solenoid mechanism, as desired. The mechanism 54 is herein illustrated as of a pneumatic type comprising a pneumatic piston 56 .reciprocally operable within an operating cylinder 58. The entrance of highpressure gas, such as compressed air, for example, from a reservoi-r tank 60, as controlled by a closing valve `62, diagrammatically illustrated, effects downward closing movement of the pneumatic piston 56, and hence closing of the interrupter 10. There are three such mechanisms 54 supplied for the three pole-units A, B and C due to the size and weight of the interrupter 10, which is suitable for 500 kv. service at an interrupting capacity of 35,000 mva. The three operating mechanisms 54 are synchronously controlled by electrical means. Reference may be had to United States Patent 2,917,602, issued December 15, 1959, to R. C. Van Sickle for a typical pneumatic mechanism adaptable for reolosing service. The operating mechanism 54 is such as to effect downward closing movement of an operating rod 64, the 4latte-r being pivotally connected, as at 66, toa main operating crank 68. The operating crank 68 is pivotally mounted upon a fixed operating shaft 70. Pivotally connected, as at 72, to this operating crank 68 is a floating link 74, which is also pivotally connected, as at 76, to a double-ended crank-arm assembly 78. The doubleended crank-arm assembly 78 is pivotally connected, as at S0 and 82, to two horizontally-extending operating rods 84 and 86. The horizontal operating rods 84, 86 have accelerating spring assemblies 88, which supply energy for moving them to the open position. The horizontal operating rods 84, 86 are pivotally connected, as at 92, 94 and 96, to three crank-arms 98, 11H1 and 102, which are afxed to three horizontally-extending main drive shafts 104, 106 and 108. The drive shafts 104, 106 and 108 rotatably pass through gas-tight seals into lower column housings 110, 112 and 114 disposed at the lower ends of the three insulating column structures 22.

Disposed interiorly within the lower column housings 110, 112 and 114 are -operating cranks 116, 118 and 1211, which, in turn, are pivotally connected, as at 122, 124 and 126, to the lower ends of vertically-extending and reciprocally-moving insulating operating rods 12S, 130

and 132. The upper ends of the three insulating operating `rods 128, 130 and 132 have metallic Irod-ends 134 (FIG. 10), which, in turn, are pivotally connected, las `at 136, to main bifurcated operating lever portions 138e, more particularly shown in FIGS, 24-27 of the drawings, and constituting integral portions of crankarm assemblies, generally designated by the reference numeral 138. Each crank-arm assembly 138 has operating `arm portions, more fully described hereinafter, and translates vertical reciprocal movement of the insulating operating rods 128, 130 and 132 into rotating contact motion and blast-Valve operation, as more fully described hereinafter.

Provided interiorly within each of the interrupting heads 28, land xedly secured to it, is a stationary main frame support 139, more particularly shown in FIGS. 28-30 of the drawings. As shown in FIGS. 28-30, the main supporting frame 139 comprises a heavy supporting base plate 140 and upstanding supports 142, 144 rigidly fastened thereto, as by welding, to form journal portions 146 for accommodating .a main operating shaft 148. The main crank-arm assembly 138, more particularly illustrated in FIGS. 24-27 of the drawings, is pivotally mounted upon the main operating shaft 148. The main ycrank-arm assembly 138 has .a bifurcated integral arm portion 138b with apertures 158 extending through the outer free ends thereof to accommodate a pivot pin 152, the latter being pivotally connected to a floating link 154, which, in turn, is pivotally connected by a pin 156 (FIG. 6) extending through an off-standing bifurcated operating arm portion 158 of the bridging contact crossarm assembly 38.

With reference to FIGS. 3 and 6 of the drawings, it will be noted that each bridging contact cross-arm assembly 38 comprises the pair of radially outwardly-extending gas-conducting moving contact arms 40, to the outer free ends of which are secured the movable contact structures 42. Each movable contact structure 42 comprises a movable tubular arcing horn 160 and a plurality of surrounding circumferentially-disposed spring-biased main contact fingers 162. The main spring-biased contact fingers 162 `conductively engage `with the outer sides of the stationary tubular contact structure 44, more clearly illustrated in FIG. 6 of the drawings.

During the opening operation, the main contact lingers 162 are first separated from the outer sides of the tubular main stationary contact 44 to effect arc establishment 46 (FIG. 6) between the movable tubular arcing horn 160 4and the stationary tubular contact 44 thereby preventing arc erosion at the main movable contact fingers 162. Arc extinction takes place as a result of a double venting blast action, as illustrated more clearly by the gas-flow arrows 164 in FIG. 6 of the drawings, and as described in more detail hereinafter. As shown, the movable contact structure 42 comprises the movable tubular arcing horn 160 having a flanged base portion 166 secured by means, not shown, to the outer extremity of the gasconducting contact arm 40 of the contact bridging crossarm assembly 38. 'In addition, a cylindrically-shaped Spring seat retainer 168 accommodates the outer ends of a plurality of contact biasing springs 170, which serve to bias the contact fingers 162 radially inwardly into good contacting engagement with the stationary tubular main contact 44.

As shown more clearly in FIGS. 6 and 7 of the drawings, the rotatable cross-arm assembly 38 includes a pair of spaced side plates 172, 174 having journal openings 176, 178 provided therein, which, in conjunction with bearings 180, 182 (FIG. 7), serve to rotatably support the cross-arm assembly 38 on an apertured bearing and blast-valve support generally designated by the reference numeral 184. The apertured bearing support 184, as shown in FIGS. 7, 7A, is iixedly secured by bolts 186 to the auxiliary reservoir chamber 24. During the opening operation, opening of a cylindrically-shaped `blast-valve 188, as shown in FIG. 7, will permit the blasting of high-pressure arc-extinguishing gas, such as sulfurhexafiuoride (SF6) gas from the auxiliary gas reservoir 24, out through openings 190 provided in the side guidewall portion of the blast-valve 188, and through openings 192 provided in the bearing and blast-valve support 184, through the gas-conducting arms 40 and toward the intercontact region to effect extinction of the established arc 46.

Preferably, in order to effect more accurate guiding of the gas blast, an insulating orifice structure 194 is provided, 'being movable with the movable contact structure 42 to effect a directional ow of the compressed gas through the vented moving and stationary contacts 42, `44, as shown in FIG. 6 of the drawings. In more detail, the orice structure 194 has a mounting flange portion 196, which is clamped by a clamping ring 198 to the end of each rotating arm 40. Each stationary tubular arcing contact 44 has a plurality of venting slots 280 provided therein to assist in venting of the compressed arc-extinguishing gas 282.

Blast-value operating linkage (FIGS. 4, 8)

The blast-Valve operating linkage 204, in general, comprises the cam-'actuated blast-valve 188, which functions to open and to permit a blasting of arc-extinguishing gas 202 only during the opening operation of the circuit interrupter 16. As shown more in detail in FIG. 9 of the drawings, the main operating crank-arm assembly 138 has a 4bifurcated arm portion 138C integrally formed therewith, which is pivotally connected by a pin 206 to a floating link 208, the latter, in turn, being pivotally connected by a pivot pin 218 to a double-armed blast-valve cam-operating lever 212 (FIG. 9 and FIG. 18) stationarily pivotally mounted upon a stationary pivot pin 214. The pivot pin 214 is journaled within upright stationary supports 216, 218 (FIG. 28) welded to the base plate 140 of the main frame support 139. Disposed between the outer ends of the double-armed blast-valve cam-operating lever 212, and pivotally mounted upon a pivot pin 220, is a pair of -contiguously-disposed operating dogs, or latches 222, 224, which have diiTerent-length nose portions 226, which engage with teeth 228 provided at the outer free end of a blast-valve cam 230. The blast-valve cam 238 is shown more clearly in FIGS. 16 and 17 of the drawings, and is also pivotally mounted upon the pivot pin 214 between the furcations 232, 234 of the bifurcated blast-valve cam-operating lever 212. A pair of compression springs 236 (FIG. 9) are provided to bias the tail portions 238 of the operating latches 222, 224 into operating engagement with the teeth 228. In more detail, the compression springs 236 seat within recesses 240 provided in a transverse movable support 242 xedly secured, as by welding, to the outer free ends of the bifurcated blast-valve cam-operating lever 212.

During the opening operation, the clockwise opening rotative motion of the main operating lever 138 effects, through straightening of the links 138C, 208, counterclockwise opening motion of the blast-valve cam-operating lever 212, and, as a result, also counterclockwise opening camming motion of the blast-valve cam 230 about the pivot axis 214. This camming action takes place in opposition to the opposing forces exerted by the blastvalve and by a compression spring 244, which seats between an ot-jutting bracket portion 246 of the main frame 139 and a spring seat 248 movable with a springguide rod assembly 250. The spring-guide rod assembly 250 is pivotally connected by a pivot pin 252 to an apertured bifurcated portion 254 of the pivotally-mounted cam 231). The camming action exerted by the blastvalve cam 230 upon a roller assembly 256, carried by a blast-valve operating lever 258, opens the blast-valve by causing clockwise (FIG. 8) motion of the blast-valve operating lever 258, more clearly shown in FIGS. 14 and 15 of the drawings. With reference to FIGS. 14 and 15 of the drawings, the blast-valve operating lever 258 is of 

1. A HIGH-VOLTAGE COMPRESSED-GAS CIRCUIT INTERRUPTER INCLUDING AN UPSTANDING INSULATING COLUMN STRUCTURE, AN INSULATING OPERATING ROD EXTENDING UPWARDLY INTERIORLY OF SAID COLUMN STRUCTURE, AN INTERRUPTING HEAD SURMOUNTED UPON SAID COLUMN STRUCTURE AND HAVING A PAIR OF TERMINAL BUSHINGS EXTENDING THEREWITH, A PAIR OF SPACED STATIONARY CONTACTS SECURED TO THE INTERIOR ENDS OF THE TERMINAL BUSHINGS, A ROTATIVE HOLLOW CROSS-ARM BRIDGING CONTACT ASSEMBLY ADAPTABLE FOR ROTATION IN A SINGLE DIRECTION ABOUT AN AXIS, SAID ROTATIVE BRIDGING CONTACT ASSEMBLY MAKING SEPARABLE ENGAGEMENT WITH THE PAIR OF SPACED STATIONARY 